Sheet folding apparatus are known wherein a sheet may be folded into one of a number of configurations. The sheet may have a single fold involving an overlap of one end to another, it may have an accordian fold which is a generally Z-shaped cross-sectional fold, it may have a standard fold wherein two folds are made with one of the panels being inserted in the other two, or it may have a double fold wherein the sheet is first folded in half and then folded in half once more to form four overlapping panels. Examples of such apparatus may be found in U.S. Pat. Nos. 3,495,818 and 3,516,655, which are assigned to the assignee of this patent application.
Although prior folding apparatus work well for single sheets or for even double sheets, a problem arises when one wishes to fold a document containing a plurality of sheets thereby obtaining a relatively great thickness in the folded document. The particular problem arises in that the space between the rollers of the apparatus cannot accomodate these various thicknesses because if the rollers are too far apart, they could not conveniently transport single sheets but if they are too close together, they could not accomodate a document having multi-sheets as the same would tend to wrinkle while passing between the rollers. It obviously would be desirable to have a document folding apparatus which would be capable of accomodating documents of different thicknesses, especially when succeeding documents fed into the apparatus are of different thicknesses.